1) When a gai-jin, foreigner, breaks Japanese cultural conventions intentionally or mistakenly, and then ignores anyone who tries give a reproach for their behavior.

2) Pretending not to understand the Japanese language and intentionally speaking bad Japanese to get out of any situation.

1) "Fuck yeah I gaijin smashed all of those hairless fuckers when I cannon-balled the onsen (hot spring) without washing off first!"

2) "I had to use my best gaijin smash twice today man. First, lost my train ticket so I was like 'doku ga iku (poison is going) haiku ticket man?' and the staff was like 'mada baka gaijinka? (another stuipid foreigner?)' and let me pass. Second, I was speeding in the rental car and I ran a red light. When the cop pulled me over, I showed him my international driving permit and said 'Nihon....go... ta... ta... tabemas.... Nihongotabemas....en.... Nihongo tabemasen....ka? (Shall we eat the Japanese language?).' To which he promptly gave me my permit and said very loudly 'Red is Stop! No again! Red.... stop!' and drove away happy to rid of the baka gaijin.

The Urban Dictionary T-Shirt

To art of getting away with douchebaggery in Japan and being an ignorant obnoxious foreigner by simply pulling a gaijin smash on their Japanese asses when the shit hits the fan

"I was supposed to give up my priority seat on the train to that old bag but I totally gaijin smashed her ass and acted like I didn't know what the fuck she was bitching at me about"

"I was too cheap and lazy to buy a subway ticket so with JR pass in hand I gaijin smashed my way through the gate before the electric doors could close and then when the guy came running after me and told me I had to buy a ticket I acted like I thought the JR pass covered everything"